over the pancreas on to the inferior surface of the diaphragm, and thence on to the caudate lobe and caudate process of the liver to the fossa from the ductus venosus and the porta of the liver. Traced to the right, it is continuous over the inferior vena cava with the posterior wall of the main cavity. From the liver it is carried downward to the lesser curvature of the stomach and the commencement of the duodenum as the posterior layer of the lesser omentum, and is continuous on the right, around the hepatic artery, bile duct, and portal vein, with the anterior layer of this omentum. The posterior layer of the lesser omentum is carried down as a covering for the postero-inferior surfaces of the stomach and commencement of the duodenum, and is continued downward as the deep layer of the gastrocolic ligament or greater omentum. From the free margin of this fold it is reflected upward on itself to the anterior and superior surfaces of the transverse colon, and thence as the superior layer of the transverse mesocolon to the anterior border of the pancreas, the level from which a start was made. It will be seen that the loop formed by the wall of the omental bursa below the transverse colon follows, and is closely applied to, the deep surface of that formed by the peritoneum of the main cavity, and that the greater omentum or large fold of peritoneum which hangs in front of the small intestine therefore consists of four layers, two anterior and two posterior separated by the potential cavity of the omental bursa.

Horizontal Disposition of the Peritoneum.Below the transverse colon the arrangement is simple, as it includes only the main cavity; above the level of the transverse colon it is more complicated on account of the existence of the omental bursa. Below the transverse colon it may be considered in the two regions, viz., in the pelvis and in the abdomen proper.

(1) In the Pelvis.The peritoneum here follows closely the surfaces of the pelvic viscera and the inequalities of the pelvic walls, and presents important differences in the two sexes. (a) In the male(Fig. 1037) it encircles the sigmoid colon, from which it is reflected to the posterior wall of the pelvis as a fold, the sigmoid mesocolon. It then leaves the sides and, finally, the front of the rectum,